Results from Realfast Transient Search System at VLA

Fast Radio Bursts (FRBs) are bright millisecond duration radio transients of extragalactic origin. Since their discovery in 2007, ~150 such bursts have been reported so far, of which 20 show repeat bursts. Localization of FRBs to ~arcsecond precision is necessary for confident host association and is essential to understanding their progenitors. Localization is also useful for studying FRB environments, host galaxy electron densities, and the structure of intervening media. Up till now, around 10-20 FRBs have been localized to a host galaxy. The host galaxies of these FRBs show a wide variety of properties consistent with hosts of other transient channels (SGRBs, CC- and Type Ia SNe). It is not yet clear if repeating and non-repeating FRBs are a part of a single population, or if they have different origins. Realfast is a commensal FRB detection system on the Karl G. Jansky Very Large Array (VLA), which can detect and precisely localize FRBs in real-time by performing fast imaging (~5ms) of de-dispersed data. In this presentation, I will talk about recent FRB localizations of a non-repeating and two repeating FRBs using the Realfast system, which has enabled us to identify their associated host galaxies using optical follow-up observations. I will further discuss the properties of these host galaxies, and how they might favor different progenitor channels for repeating and non-repeating FRBs. One of these repeaters has shown some really interesting properties. It is very similar to the first repeater FRB121102, challenging the notion that FRB121102 is an outlier and indicating that repeating FRBs also show a wide range of properties.